Fluorescent article for use in the graphic arts and method of making same



Sept. 26, 1961 ARTS AND MET Filed Aug. 27, 1957 H. T. HOLSAPPLE FLUORESCENT ARTICLE FOR USE IN THE GRAPHIC HOD OF MAKING SAME fla lab

INVENTOR. x HARVEY 7.' HOLSAFPLE' ATTOPNFY United Sttes Patent O 3,001,311 FLUORESCENT ARTICLE FOR USE IN THE SGlAIIIHIC ARTS AND METHOD 0F MAKING M Harvey T. Holsapple, Minneapolis, Minn., assignor to Kemart Corporation, San Francisco, Calif., a corporation of California Filed Aug. 27, 1957, Ser. No. 680,578 Claims. (Cl. 41-26) This invention relates to improvements in the graphic arts, and more particularly to improvements in the art of preparing pre-separated color copy and to artists materials useful in such art.

It is an object of this invention to provide simple means and easily used materials for adapting ordinary black and white copy to pre-separated color copy preparatory to making color separations.

It is a further object of this invention to provide preseparated color copy which results in color separations having an unusual clarity of tone.

It is an additional object of this invention to provide improved means simplifying the work of the artist in making pre-separated color copy.

It is another object of this invention to provide color copy which the photoengraver can use more easily and more rapidly than he can use the known best prior art.

It is still another object of this invention to provide pre-separated color copy giving the artist a faithful visual impression of the final reproduction to be made from the color separations while he is preparing the copy and giving the observer of the completed color copy the same faithful visual impression.

The foregoing and other objects of applicants invention will become clear upon an understanding of the following written description considered in connection with the appended claims.

Before discussing the instant disclosures, an understanding of pre-separated art techniques should be helpful in understanding the present status of the art and the problems inherent in existing techniques and materials.

A typical exempliiication of the prior art is the socalled Bourges Color Copy, described in Color by Over-printing, written by Donald E. Cooke, and published by The John C. Winston Company, copyright 1955; and as described in an article entitled Pre-separated Art Techniques by Herbert T. Paschel, and published in Modern Lithography for September, 1956,'page 49. cSo far as applicant knows, this procedure represents the furthest prior advance in the pre-separated color art.

Under the prior art Bourges process, a black and white drawing, in line or tone, is made using conventional art techniques. This drawing is otherwise known as the key drawing. With the key drawing as a guide, the artist prepares a set of three overlay sheets, one in each of the process colors, yellow, red and blue. These overlay sheets are plastic sheets containing a layer of uniformtink color in tint in strengths from to 100%. The artist removes the color layer from undesired spots by means of a stylus or liquid. Each of these overlay sheets is hinged to the drawing so that each or all can be superimposed over the drawing. The' artist then proceeds to remove color from each overlay, one at a time, in all areas where that particular color is not needed.

The disadvantage of this procedure is that the artist must select the general color value which he desires from one of a plurality of different tint strength sheets and then must remove the undesired color. This means that the artist must have a large inventory of plastic 3,001,311 Patented Sept. 26, 1961 sheets and that, at least for the darker tones, the artist works blindly. In addition, the artist must add additional color with matching pencils and liquids in the event he desires to strengthen color over the starting sheet.

Another disadvantage is that a proper exposure of the colored portions of each lnished overlay sheet does not result in a completed dot elimination in the noncolored portions of the overlay sheet. This results in halftone dots of the color in question to a slight degree in unwanted portions of the nal reproduction, thereby distorting the true color values, unless special treatment or highlight masks are provided.

It will appear from a description of the within procedures that the applicant has developed a procedure and materials which enable the artist to use a minimum inventory of artists supplies .and to produce overl-ay sheets in complete view of the key drawing and which enable the -photoengraver to produce faithfully color separations without the need for special treatment or highlight masks.

`In the drawings:

FIG. 1 is a plan view of a black and white key drawing used in the preparation of the pre-Separated color copy of this invention;

FIG. 2 is a plan view of a yellow color overlay made in accordance with this invention;

FIG. 3 is a plan view of a red color overlay made in accordance with this invention;

FIG. 4 is a plan view of a blue color overlay made in accordance with this invention;

FIG. 5 is a sectional view of the plastic sheeting usedl i several steps in making the color separation overlays of this invention.

In the practice of this invention a black and white drawing, either in tone or in line, is made using conventional art techniques. As illustrated in FIG. 1, the illustrative black and white drawing comprises a line drawing of a sailboat upon a seascape. For the illustrative example, this drawing is made in accordance with the teachings of the `Burtt L. Berry Patent 2,395,986, issued March 5, 1946, for Half-tone Drop-out Process. In the example, it is desired to have finished color copy in which the sky is blue, the sun is orange, theI sea is green, the hull of the boat is red, the sails are white, and the mast and boom are yellow.

In order to accomplish this result, the color overlay sheet of FIG. 2 is axed to one margin of'the drawing of FIG. 1; the color overlay of FIG. 3 is: afnxed to a second margin of the drawing of FIG. 1; and the color overlay of FIG. 4 is aiiixed to a third margin of FIG. 1.

Color overlay sheet 2 is provided with yellow coloring as indicated in cross-hatching; the color overlay of FIG. 3 is provided with red coloring as shown in the cross-hatching; and the color overlay of FIG. 4 is provided with blue coloring as shown by the cross-hatching, all in accord with specific procedures set forth later in this application.

In general, the foregoing disclosure constitutes a part of the prior art and is used in prior art procedures, such as for examule the Bourges process referred to above.

This invention refers to improved artists materials and tilm l0, a second substantially colorless fluorescent layer 12 adhered to the other surface of lm 10, and a transparent colored layer 13 strippably adhered to the layer 12. The fluorescent layers 11 and l2 are adhesively adhered to the transparent plastic base sheet 10, and the transparent colored layer 13 is adhesively adhered to the fluorescent layer 12.

The layers 11 and 12 have the power of absorbing dyestutfs in solution, as appears later in this specification.

The coefficient of adhesion between the transparent uorescent layer 12 and the transparent plastic lm l0 is greater than the coetiicient of adhesion between the transparent colored layer 13 and the fluorescent layer 12, so that the transparent colored layer 13 may be stripped from the tluorescent layer 12l without offsetting the fluorescent layer 12 from the transparent plastic lilm 10.

In actual practice, applicant uses commercially obtainable transparent cellulose acetate sheeting coated on both sides with a gelatin film, such as for example the gelatin lm obtainable from General Aniline and Film Company under its trade-mark Ansco andunder its trade designation Graphic Base Film.

This lm is dipped into a substantially colorless ultraviolet-activatable fluorescent solution. By way of illustration, a suitable solution is made with 1 gallon of water; in which 38 grams of a colorless blancophor fluorescent dyesu, as for example General Dyestuffs Blancophor HS76, is dissolved; to which 25 cubic centimeters of butyl alcohol is added as a wetting agent. The gelatin coating on the film absorbs the lluorescent solution, thereby providing a sandwich structure comprising the transparent plastic lilm 10, the lower substantially colorless fluorescent layer 11 and the upper substantially colorless fluorescent layer 12.

To complete the sandwich structure illustrated in FIG. 5, the transparent color layer 13 is applied over the upper iluorescent layer 12. By way'of illustration, the applicant uses a commercially available frisket lacquer tinted with a bright green dye. One commercially available frisket lacquer is that produced by the Glidden Paint Company under its trade designation Strip Coat Lacquer. Generically, this product is known to the art as a lacquer made by dissolving a vinyl resin in -rnethyl iso butyl ketone. It is colored in the specic example here given with an oil soluble green dyestui.

The resulting structure is sulliciently transparent so that several sheets of the material may be superimposed over the drawing of FIG. 1 and still render the black and white portions of the drawing clearly perceptible to the artist. The gelatin layers 11 and 12 have the power to absorb dyestutfs in solution. The frisket lacquer is waterproof and has a lesser adhesion for the gelatin layer 12 than the gelatin layer 12 has for the cellulose acetate sheeting 10, thereby enabling the artist, in a way to be disclosed later in this application, to strip the frisket lacquer from the sandwich structure without offsetting the gelatin layer.

The foregoing basic sheeting is used for each of the color overlays and the various colors and shadings are obtainable, not by the use of ditferent colored transparent sheetings, but by the application of colored dyestutfs to the gelatin layer 12 of the sandwich structure in the manner later described in this specification.

The several liquid colors, yellow, red and blue, each comprises a transparent, substantially non-fluorescent, lluorescence-quenching, ultraviolet-absorbing colored dyestuff which is soluble in the gelatin layer and which has a color equivalent in shade and brightness to the color of the printing inks Which are to be used to reproduce the finished copy. The vehicle for the liquid colors, moreover, should be incapable of dissolving the frisket layer 13.

By way of example, applicant assumes that the linal reproduction is to be printed with the standard process printing inks commonly used in the graphic arts industry.

In this case the formulae for the several colored materials are set forth below:

Red and Neptune Blue BRA are commercially obtainable dyestutls, and applicant has purchased them under said designations from General Dyestuffs Corporation.

The nickel chloride solution referred to in the foregoing formulae is made by taking grams of nickel chloride and adding enough water to make 'one gallon of solution.

The several colored solutions set forth above are applied to the sandwich structure of FIG. 5 in the manner disclosed in FIGS. 6 to l0, both inclusive.

First, the artist views the drawing and determines each section or portion of the drawing which is to have the particular color in question upon completion of the overlay sheet. With a sharp knife, the artist makes a cut 14 through the colored layer 13 and in vertical alignment with and outlining the margins of the area to be colored. The cut will ordinarily also go through the fluorescent layer 12, but this is neither necessary nor harmful. Viewing FIG. 6, a marginal portion of the fluorescent layer 12 which is to be colored is designated 12a, and a marginal portion of the tluorescent layer 12 which is to remain uncolored is designated 12b. The marginal portions of the transparent colored layer 13 overlaying portions 12a and 12b of the fluorescent layer 12 are similarly lettered 13a and 13b.

Next, the operator strips from each portion 12a of the fluorescent layer the related overlay portion 13a of the transparent colored frisket layer, as appears in FIG. 7. This procedure gives the artist access to the fluorescent layer overlying the desired portion of the key drawing and protects the balance of the fluorescent layer from being altered during the subsequent steps of the process.

Next, the artist with the use of an ordinary paint brush fully loaded with the desired liquid color ows the desired liquid color 15, as shown in FIG. 8, onto the colored overlay sheet with a liberal wash. Because of the frisket layer, the artist need not exercise critical care in this operation.

The artist waits about a minute, during which the liquid dyestutf will go into solid solution into the portion 12a of the transparent fluorescent layer (see FIG. 9). He then wipes the excess liquid color from the overlay sheet with a slightly damp sponge. In so doing, the dyestul colors the transparent layer the desired color and also quenches or destroys the lluorescence of the area in question. In addition, the dyestuff absorbs ultraviolet which might otherwise excite liuorescence of the corresponding portion of underlying iluorescent layer 11.

The linal step in the preparation of the colored overlay sheeting consists in removing the balance of the transparent colored layer 13b (see FIG. 10).

The colored overlay sheet thus made is shown in FIG. 2. It comprises a portion 12a of the uorescent layer 12 colored with the yellow dyestul. This portion has a clear transparent yellow color and is substantially nonfluorescent. The balance of the drawing in FIG. 2 comprises a colorless fluorescent portion 12b.

The same procedures are followed in producing the red and the blue overlay sheets illustrated in FIGS. 3 and 4, where similar reference numerals are used to indicate similar areas of the drawing.

After the foregoing copy has been made, color separations are produced, one a black and white separation in accordance with FIG. 1, and one for each of the colors, as in FIGS. 2, 3 and 4. In making the separation of FIG. l, all of the color overlay sheets are laid back; and in exposing the color overlays of FIGS. 2, 3 and 4, only one color overlay sheet is used at a time with a piece of white paper behind it.

For complete drop-out of the non-colored areas and for complete drop-out of non-desired colors, it is recommended that two exposures be made for each separation, one a normal white light exposure with the halftone screen in place, and the other an exposure under ultraviolet illumination with the vhalftolne screen removed or displaced. These procedures are not described here in detail, since they are well known to the art, being described for example in the Burtt- L. Berry Patent 2,395,- 985, patented March 5, 1946, for Half-tone Highlight Process, and the Burtt L. Berry Patent 2,395,986, patented March 5, 1946, for Half-tone Drop-out Process.

In making the halftone color separations, it is unnecessary to use filters for color separation between the copy and the film. This is true because each of the color overlays is photographically effective with respect to the desired colors only. If orthochromatic film is used, a

filter changing the color to black is necessary. For the red separation a light green filter is used; for the yellow separation a rose filter is used; and for the blue separation a yellow filter is used.

The foregoing procedure describes the operation of this method with uniform color shading, the materials described above having further utility in that lighter shadings of the color tone and variations in the color tone are obtainable without a large inventory of various artists materials. The characteristics of the materials described are such that the colors may be diluted to any desired degree by the use of a simple thinner. The thinner to be used quenches fluorescence in the top layer 12 and absorbs ultraviolet which would otherwise be transmitted to the bottom layer 11 so that the fluorescence of both gelatin layers will be prevented, regardless of how thin the colored solution is made. Arsuitable solution is made by dissolving 80 grams of copper sulphate in 1 gallon vof distilled water and adding 2 ounces of a 14 Baum gum arabic solution. This solution is thoroughly mixed and filtered. 16 oz. of this base solution is then mixed with 2 oz. of glycerne. The resulting fluid is bottled and is used for thinning the respective colors set forth above.

The foregoing artists materials and procedures offer the artist and platemaker benefits and advantages heretofore unobtainable in pre-separated color methods. They make it unnecessary for the artist to scrape away pre-applied colors. They reduce the expensive and confusing inventories. They enable the artist to develop his artwork on separate color overlays, one superimposed over another and to see the finished artwork in its true colors just as the printer or lithographer will reproduce them. They eliminate that color degradation present in even the best of the prior art. It has been found in actual practice that the time for making color separations is but a fraction of the best of the prior art and that the quality of the finished product surpasses the best of the prior art that has come to the applicants attention.

It will become apparent to those skilled in the art that numerous advantages in addition to those specifically pointed out in the foregoing description are inherent in the artists materials and in the procedures disclosed above.

For example, if the artist makes a mistake and colors a portion of the gelatin film which should have been uncovered, he need only take a scraper, scrape ofi the colored gelatinand the fluorescence from the bottom layer will become photographically effective. In addition, in the event that the artist accidentally removes too -much of the frisket lacquer, liquid frisket lacquer can be applied to repair the damage.

The color overlay sheets and the liquid colors of this invention and the procedures herein described may also be used in connection with an ordinary black and White photograph as the key copy. In this instance, the color overlay sheets are made in the manner described above. The black and white separation is made of the photograph itself in the usual halftone method. The color separations are made by placing a sheet of white paper underneath each color overlay sheet and taking a white light halftonc exposure. With the white sheet still in place, a supplementary exposure is made with ultraviolet. The finished separations do not have the usual fault of the dark tones of the key drawing repeating themselves in each color separation.

Some of the advantages of this invention may be obtained even if the gelatin layers 11 and 12 are non-liucrescent. In this case, a plain fluorescent sheet, such as that disclosed in the Burtt L. Berry Patent 2,395,986. patented March 5, 1946, for Half-tone Drop-out Process, is placed behind the finished color overlay sheet and two exposures are made, as disclosed in the aforesaid Berry patent, for each color separation. Some of the results of this invention may also be obtained if a piece of ordinary reflective white paper is placed behind such a color overlay sheet and two exposures with ultraviolet light only are made in the manner disclosed in Walter S. Marx, Ir. Patent 2,191,939, issued on February 27, 1940, for Photoengraving.

Having thus described a selected embodiment of my invention, it will become apparent to those skilled in the art that other modifications may be practiced and that equivalent materials may be substituted for those de-y scribed above, so long as the practitioner remains within the boundaries of the invention as defined within the appended claims. With this understanding, the invention is claimed as follows.

I claim:

l. An article of manufacture comprising a transparent, colorless, plastic film; a normally colorless, normally fluorescent, layer excitable in response to ultraviolet and overlying at least one surface of said plastic film; and a transparent, colored, ultraviolet-absorbing, fluorescencequenchingmaterial disposed in preselected portions only of said fluorescent layer.

2. An article of manufacture comprising a transparent, colorless, plastic film; a normally colorless gelatinous layer overlying at least one surface of said plastic film; a normally colorless, normally fluorescent dyestui excitable in response to ultraviolet in said gelatinous layer; and a transparent, colored, ultraviolet-absorbing, fluorescencequenching material disposed in preselected portions only of said gelatinous layer.

3. An article of manufacture comprising a transparent, colorless, cellulose acetate film; a normally colorless, gelatinous layer overlying at least one surface of said acetate film; a substantially colorless, normally fluorescent dyestuff excitable in response to ultraviolet in said gelatinous layer; and a transparent, colored ultraviolet-absorbing, fluorescence-quenching material disposed in preselected portions only of said gelatinous layer.

4. The method of making pre-separated color copy from a colorless, transparent, plastic lm having a normally colorless, transparent, dye dissolvent, fluorescent layer excitable in response to ultraviolet and adhered to at least one surface of said film and provided with a transparent, colored, strippable layer which comprises making a cut around the margin of a preselected portion of said strippable layer; removing the portion of said strippable layer within said margin; dyeing said fluorescent layer with a transparent, non-fluorescent, fluorescence-quenching, ultraviolet-absorbing, colored dyestui; waiting until said dyestuif has gone into solution in said fluorescent material; wiping off any excess dyestuff; and removing the balance of said strippable layer.

5. The method of making pre-separated color copy from a colorless, transparent, plastic film having a normally colorless, transparent, dye dissolvent, fluorescent layer excitable in response to ultraviolet and adhered to at least one surface of said film, which comprises dyeing preselected portions of said fluorescent layer with a transparent, non-fluorescent, uorescence-quenching, ultraviolet-absorbing, colored dyestut.

References Cited in the le of this patent UNITED STATES PATENTS Re. 22,421 Rudnick Ian. 18, 1944 1,429,445 Merritt Sept. 19, 1922 1,913,881 Heinecke June 13, 1933 2,076,984 Eggert et al Apr. 13, 1937 8 Murray n Feb. 15, 1938 Eggert et al. Mar. 21, 1939 Krieger et a1 June 13, 1939 Bennett Feb. 27, 1940 Bassist Nov. 10, 1942 McIntosh Nov. 10, 1942 Corwin Nov. 9, 1943 Bourges Dec. 14, 1943 Sanders Oct. 17, 1944 Berry Mar. 5, 1946 Land Apr. 20, 1948 McGraw et al. Ian. 27, 1953 Switzer Mar. 3, 1953 Switzer et al. Sept. 22, 1953 Marx f..-....-....-- Aug. 31, 1954 Purdy Feb. 7. 1956 Marx Nov. 13, 1956 Eichorn Aug. 6, 1957 OTHER REFERENCES 20 Kemart Fluorostop-Its Use In Color Correction by F. P. Adams, The Photoengravers Bulletin, November 1950; pp. 109-111. 

1. AN ARTICLE OF MANUFACTURE COMPRISING A TRANSPARENT, COLORLESS, PLASTIC FILM; A NORMALLY COLORLESS, NORMALLY FLUORESCENT, LAYER EXCITABLE IN RESPONSE TO ULTRAVIOLET AND OVERLYING AT LEAST ONE SURFACE OF SAID PLASTIC FILM; AND A TRANSPARENT, COLORED, ULTRAVIOLET-ABSORBING, FLUORESCENCEQUENCHING MATERIAL DISPOSED IN PRESELECTED PORTIONS ONLY OF SAID FLUORESCENT LAYER. 